Twins Become Social at 14 Weeks Gestation
Italian Researchers from the University of Turin and the University of Parma tracked the motions of 5 sets of twins during gestation to study how twins interact with each other before birth. Doctors have known for years that fetuses can control their actions in the womb. This time researchers wanted to know if twin’s purposeful bodily control was different than single occupant fetuses. Their findings were published in October’s PLoS ONE. They used ultrasonography (which images internal body structures) on each set of twins in daily, 20 minute sessions. What they found changes what a lot of doctors thought they knew about the emergence of social behavior. Identical Twins it turns out begin purposefully touching each other as early as the 14th week of gestation. At first the touches the scientists observed were tentative, but as the twins developed they spent more and more time exploring. In fact, by 18 weeks the twins were spending more time in contact with their partners than they were with the walls of the uterus or even themselves. At 18 weeks 30% of all their movements were directed at their womb mates. The twins not only spent a lot of time in purposeful contact with each other but the movements directed at each other were more accurate than movements directed at themselves. In other words, a fetus who is a twin knows his twin better than he knows himself, or at least he’s more interested in his twin than he is in himself.
What Does this Mean?
It doesn’t mean much just by itself. I want to know if the interaction that identical twins have in the womb changes their developmental trajectory from the start compared to singles or fraternal twins. I’m a twin, but I’m a fraternal twin. That means that my sister and I didn’t have the same amniotic sack. This research doesn’t apply to us. Nevertheless, my twin and I know each other pretty well, and any twin related research is always of interest to me. Something I’d like to know, that isn’t covered within the scope of the research is if twin displayed social interactions translate to some altered adult psychology. I’m not as interested in how twins interact in the womb as I am in the implication of those interactions through childhood and adulthood. If twins really do behave markedly different than other fetuses in the womb, then I want to know how that psychologically changes them as they grow (if it does at all). The research is certainly interesting. It’s a good starting place, but I hope the doctors continue to study the psychological differences between twins and non twins.
Note: This was reported on in the January/February issue of Scientific American Mind Magazine. My analysis derives from that article, not the research published by the researchers themselves.